Fuel tank connector

ABSTRACT

A fuel tank connector for connecting a fuel tank and a pipe in communicating fashion includes a gas barrier member made of a synthetic resin and having a gas barrier property. The gas barrier member includes a tubular portion and a flanged portion provided on a peripheral side of the tubular portion, which extends beyond an opening of the fuel tank. The gas barrier member is made of a liquid crystal polymer, aromatic polyamide, a blended polymer of an ethylene-vinyl alcohol copolymer and high-density polyethylene, a blended polymer of polyamide and polyethylene, or a blended polymer of polyamide and high-density polyethylene.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority under 35U.S.C. 119 toJapanese Patent Applications Nos. 2000-336766, 2001-50087 and2001-307115, filed Nov. 2, 2000, Feb. 26, 2001 and Oct. 3, 2001,respectively, entitled “Fuel Tank Connector”. The contents of theseapplications are incorporated herein by reference in their entirety. Inaddition, this is a continuation of application Ser. No. 09/984,450filed Oct. 30, 2001; the disclosure of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a fuel tank connector, inparticular a connector capable of effectively decreasing leakage ofevaporative emissions from a fuel tank.

[0004] 2. Discussion of Background

[0005] As shown in FIGS. 23 and 24, a fuel tank 100 usually has a pipe101, such as a fuel feeding pipe and a pipe for guiding gas generatingfrom the fuel, connected thereto. The connection of the pipe 101 is madeby use of a connector 110 fitted to the fuel tank 100 as shown in FIGS.23 and 24.

[0006] The connector 110, which is shown in FIGS. 23 and 24, includes atubular portion 111 for connection with the pipe 101, a flanged portion112 projecting laterally from a peripheral portion of one end of thetubular portion 111 melt-bonded to the tank 100 so as to cover anopening 100 a in the tank 100, and a fuel cutoff valve 113 provided inthe flanged portion 112 on a side opposite the tubular portion 111. Thetubular portion 111 and the flanged portion 112 are integrally moldedfrom high-density polyethylene.

[0007] The fuel cutoff valve 113 in the shown connector 110 includes afloat chamber forming box 113 b formed in a cylindrical shape, having avalve seat unit 113 a with a valve seat 113 a′ at the opening of a borein communication with a bore in the tubular portion 111, having a bottomopened and made of polyacetal; a float 113 c having an upper portionintegrally formed with a valve 113 e and housed in the box 113 b so asto be slidable therein; and a lid 113 d closing the opened bottom of thebox 113 b and cooperating with the box to form the float chamber withthe float 113 c incorporated therein. As the float 113 c rises, thevalve 113 e makes close contact with the valve seat 113 a′ to close theopening.

[0008] In the connector 110, the box 113 b of the fuel cutoff valve 113is configured to be integrally fitted to the flanged portion 112 so asto have an upper side of the box 113 b embedded in the flanged portion112 by, e.g., plastic molding wherein the box is integrally united tothe flanged portion with the box being inserted in a mold. A peripheralportion of the flanged portion 112 with the box 113 b is melt-bonded toa surface of the tank 100 around the opening 100 a of the tank 100 withthe box 113 b being inserted into the tank 100 through the opening 100 aof the tank 100.

[0009] In the connector 110 thus configured, the flanged portion 112 andthe tubular portion 111 are made of high-density polyethylene. Theevaporative emissions generating from the fuel in the tank 100 oranother member have been predicted to leak out, though at a regulatedvalue or less, through a portion of the flanged portion 112 providedbetween an edge of the opening 100 a of the tank and the box 113 b ofthe connector 110 melt-bonded to the tank 100.

SUMMARY OF THE INVENTION

[0010] It is an object of the present invention to provide aneasy-to-mold connector capable of effectively decreasing leakage ofevaporative emissions from a fuel tank, which is predicted in theconventional connector.

[0011] In order to attain the object, according to a first aspect of thepresent invention, there is provided a fuel tank connector adapted to befitted to an opening of a fuel tank to connect the fuel tank and a pipein communicating fashion, comprising:

[0012] a gas barrier member made of a synthetic resin having a gasbarrier property, the gas barrier member including a tubular portion anda flanged portion provided on a peripheral side of the tubular portionand having a greater side than an opening of the fuel tank;

[0013] wherein the gas barrier member is made of polybutyleneterephthalate, polyphenylene sulfide, a liquid crystal polymer,aliphatic polyketone, aromatic polyamide, a blended polymer of anethylene-vinyl alcohol copolymer and high-density polyethylene, ablended polymer of polyamide and polyethylene, a blended polymer ofpolyamide and high-density polyethylene, or polyethylene terephthalate;

[0014] the gas barrier member has at least a portion of a surfacecovered with an outer shell made of an olefin resin having an adhesiveproperty, polyethylene or high-density polyethylene; and

[0015] the outer shell includes an annular projected portion, whichcovers a leading end of the flanged portion and projects toward an outersurface of the fuel tank.

[0016] The fuel tank connector thus constructed can effectively minimizethat evaporative emissions deriving from the fuel in the fuel tank leakfrom the connector.

[0017] Additionally, the gas barrier member with the outer shell can bemelt-bonded to the fuel tank at the outer shell in reliable and easyfashion.

[0018] With regard to a fuel tank with an outer surface layer made ofhigh-density polyethylene, the connector can be fitted to the fuel tankthrough the annular projected portion of the outer shell with highbonding strength maintained, effectively minimizing the leakage of theevaporative emissions from the fuel tank by the gas barrier member.

[0019] In order to attain the object, according to a second aspect ofthe present invention, the flanged portion has a peripheral portionmelt-bonded to a synthetic resin having a gas barrier property andforming a fuel tank to fit the connector to the fuel tank, in the firstaspect.

[0020] The fuel tank connector thus constructed can further effectivelyminimize the leakage of the evaporative emissions from the fuel tank, inaddition to the advantages stated earlier.

[0021] In order to attain the object, according to a third aspect of thepresent invention, at least a portion of the outer shell made of anolefin resin having an adhesive property, and at least a portion of asurface of the gas barrier member uncovered with the outer shell arecovered with an additional outer shell made of high-densitypolyethylene, in the first or the second aspect.

[0022] In the fuel tank connector thus constructed, the outer shell,which is made of high-density polyethylene, can be fitted to the gasbarrier member in easier and more reliable fashion, allowing theconnector to be fitted to the fuel tank in more reliable and easierfashion, in addition to the advantages stated earlier.

[0023] In order to attain the object, according to a fourth aspect ofthe present invention, the gas barrier member has the leading end of theflanged portion provided with an annular projected portion, whichprojects toward the outer surface of the fuel tank, in the first, thesecond or the third aspect.

[0024] In the fuel tank connector thus constructed, design freedom infitting of the connector to the fuel tank can increase in such a mannerto effectively minimize the leakage of evaporative emissions from thefuel tank in addition to the advantages stated earlier.

[0025] In order to attain the object, according to a fifth aspect of thepresent invention, the gas barrier member has the leading end of theflanged portion provided with an annular projected portion, whichprojects toward the outer surface of the fuel tank, and the connectorhas the annular projected portion melt-bonded to the outer surface ofthe fuel tank, thereby being fitted thereto, in the first aspect.

[0026] With regard to a fuel tank with an outer layer made ofhigh-density polyethylene, the fuel tank connector thus constructed canbe fitted to the fuel tank through the annular projected portion of theouter shell and the annular projected portion of the gas barrier memberwith high bonding strength maintained, effectively minimizing theleakage of evaporative emissions from the fuel tank by the gas barriermember.

[0027] In order to attain the object, according to a sixth aspect of thepresent invention, one of the annular projected portion of the outershell and the leading end of the flanged portion of the gas barriermember has a projection formed thereon, and the outer shell is fitted tothe gas barrier member with the projection being inserted into the otherone without the projection, the outer shell being made of polyethyleneor high-density polyethylene, in the first aspect.

[0028] The fuel tank connector thus constructed can ensure to maintainthe unity of the annular projected portion provided on the leading endof the flanged portion of the gas barrier member and the annularprojected portion of the outer shell at high level.

[0029] In order to attain the object, according to a seventh aspect ofthe present invention, the gas barrier member has the leading end of theflanged portion provided with an annular projected portion, whichprojects toward the outer surface of the fuel tank and has a projectinglength substantially equal to that of the annular projected portion ofthe outer shell, and the annular projected portion of the gas barriermember and the annular projected portion of the outer shell has a cavityformed therebetween to be opened on a side of the outer surface of thetank, the outer shell made of polyethylene or high-density polyethylene,in the first aspect.

[0030] In the fuel tank connector thus constructed, when the annularprojected portion of the outer shell is heat-melted, the melted materialof polyethylene or high-density polyethylene forming the annularprojected portion can get into the cavity to melt-bond the annularprojected portion to a fuel tank, spreading the melted material ofpolyethylene or high-density polyethylene in a wide range.

[0031] When the melt-bonding is carried out to leave some part of thecavity unfilled after having melt-bonded the annular projected portionof the outer shell to the fuel tank, the unfilled part can absorb theexpansion of the gas barrier member, which could be caused by fuel orevaporative emissions from the fuel. This arrangement can make itdifficult for a force lowering the melt-bonding strength to beapplicable to the melt-bonded portion between the annular projectedportion of the outer shell and the fuel tank.

[0032] In order to attain the object, according to an eighth aspect ofthe present invention, the gas barrier member has the leading end of theflanged portion provided with an annular projected portion, whichprojects toward the outer surface of the fuel tank and has a smallerprojecting length substantially than the annular projected portion ofthe outer shell, the outer shell being made of polyethylene orhigh-density polyethylene, in the first aspect.

[0033] In the fuel tank connector thus constructed, when the annularprojected portion of the outer shell is heat-melted, the melted materialof polyethylene or high-density polyethylene forming the annularprojected portion can get into between a projecting surface of theannular projected portion of the gas barrier member and the outersurface of the fuel tank to melt-bond the annular projected portion ofthe outer shell to the fuel tank, spreading the melted material ofpolyethylene or high-density polyethylene in a wide range.

[0034] In order to attain the object, according to a ninth aspect of thepresent invention, the gas barrier member, which is covered with theouter shell, has an upper side stepwise formed so as to have a steppedsurface facing the leading end of the flanged portion of the gas barriermember, the outer shell made of polyethylene or high-densitypolyethylene, in the first aspect.

[0035] In the fuel tank connector thus constructed, even if the gasbarrier member is swollen by fuel or evaporative emissions from thefuel, the force caused by the swell can be received by an opposedsurface of the outer shell (made of polyethylene or high-densitypolyethylene) in contact with the stepped surface to be dispersed. Thisarrangement can make it difficult for a force lowering the melt-bondingstrength to be applicable to the melt-bonded portion between the annularprojected portion of the outer shell and the fuel tank.

[0036] In order to attain the object, according to a tenth aspect of thepresent invention, the fuel tank connector is used for connection with afuel feeding pipe in the first, the second, the third, the fourth, thefifth, the sixth, the seventh, the eighth or the ninth aspect.

[0037] The fuel tank connector thus constructed can connect the fuelfeeding pipe to the fuel tank in such a manner to effectively minimizethe leakage of evaporative emissions from fuel, in addition to theadvantages stated earlier.

[0038] In order to attain the object, according to an eleventh aspect ofthe present invention, the fuel tank connector is used for connectionwith a vent pipe in the first, the second, the third, the fourth, thefifth, the sixth, the seventh, the eighth or the ninth aspect.

[0039] The fuel tank connector thus constructed can connect the ventpipe to the fuel tank in such a manner to effectively minimize theleakage of evaporative emissions from fuel, in addition to theadvantages stated earlier.

[0040] In order to attain the object, according to a twelfth aspect ofthe present invention, the fuel tank connector further comprises a fuelcutoff valve in the first, the second, the third, the fourth, the fifth,the sixth, the seventh, the eighth or the ninth aspect.

[0041] The fuel tank connector thus constructed can connect a pipe tothe fuel tank through the fuel cutoff valve, effectively minimizing theleakage of evaporative emissions from fuel, in addition to theadvantages stated earlier.

[0042] As explained, the fuel tank connector according to the presentinvention, which is adapted to be fitted to an opening of a fuel tank toconnect the fuel tank and a pipe in communicating fashion, comprises thegas barrier member made of a synthetic resin and having a gas barrierproperty, the gas barrier member including the tubular portion and theflanged portion provided on the peripheral side of the tubular portionand having a greater side than the opening of the fuel tank; wherein thegas barrier member is made of polybutylene terephthalate, polyphenylenesulfide, a liquid crystal polymer, aliphatic polyketone, aromaticpolyamide, a blended polymer of an ethylene-vinyl alcohol copolymer andhigh-density polyethylene, a blended polymer of polyamide andpolyethylene, a blended polymer of polyamide and high-densitypolyethylene, or polyethylene terephthalate. This arrangement caneffectively minimize that evaporative emissions deriving from the fuelin the fuel tank leak from the fuel tank connector.

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] A more complete appreciation of the invention and many of theattendant advantages thereof will be readily obtained as the samebecomes better understood by reference to the following detaileddescription when considered in connection with the accompanyingdrawings, wherein:

[0044]FIG. 1 is a vertical cross-sectional view showing the fuel tankconnector according to a first typical embodiment of the presentinvention showing along with the essential parts of a fuel tank beforefitting the connector to the tank;

[0045]FIG. 2 is a plan view showing how the connector is put on the fueltank before fitting the connector to the tank;

[0046]FIG. 3 is a vertical cross-sectional view showing the connectoralong with the essential parts of the fuel tank after fitting theconnector to the tank;

[0047]FIG. 4 is a vertical cross-sectional view showing the fuel tankconnector according to a second typical embodiment of the presentinvention along with the essential parts of a fuel tank before fittingthe connector to the tank;

[0048]FIG. 5 is a plan view showing how the connector is put on the fueltank before fitting the connector to the tank;

[0049]FIG. 6 is a vertical cross-sectional view showing the connectoralong with the tank after fitting the connector to the tank;

[0050]FIG. 7 is a vertical cross-sectional view showing the fuel tankconnector according to a third typical embodiment of the presentinvention along with a fuel tank before fitting the connector to thetank;

[0051]FIG. 8 is a plan view showing how the connector is put on the tankbefore fitting the connector the tank;

[0052]FIG. 9 is a vertical cross-sectional view showing the connectoralong with the tank after fitting the connector to the tank;

[0053]FIG. 10 is a side view of the fuel tank connector according to afourth typical embodiment of the present invention;

[0054]FIG. 11 is a different side view of the connector shown in FIG.10;

[0055]FIG. 12 is a plan view of the connector according to the fourthembodiment;

[0056]FIG. 13 is a vertical cross-sectional view showing the connectoraccording to the fourth embodiment along with the essential parts of afuel tank before fitting the connector to the tank (in the lineXIII-XIII in FIG. 12);

[0057]FIG. 14 is a vertical cross-sectional view showing the connectoralong with the essential parts of the tank after fitting the connectorto the tank;

[0058]FIG. 15 is a cross-sectional view of the essential parts of theconnector according to the fourth embodiment (before fitting to thetank);

[0059]FIG. 16 is a cross-sectional view of the essential parts of theconnector (after fitting to the tank);

[0060]FIG. 17 is a cross-sectional view of the essential parts of amodified form of the connector shown in FIGS. 10-16 (before fitting tothe tank);

[0061]FIG. 18 is a cross-sectional view of the essential parts of themodified form (after fitting to the tank);

[0062]FIG. 19 is a cross-sectional view of the essential parts ofanother modified form of the connector shown in FIGS. 10-16 (beforefitting to the tank);

[0063]FIG. 20 is a cross-sectional view of the essential parts of themodified form shown in FIG. 19 (after fitting to the tank);

[0064]FIG. 21 is a cross-sectional view of the essential parts ofanother modified form of the connector shown in FIGS. 10-16 (beforefitting to the tank);

[0065]FIG. 22 is a cross-sectional view of the essential parts of themodified form shown in FIG. 21 (after fitting to the tank);

[0066]FIG. 23 is a vertical cross-sectional view showing a conventionalfuel tank connector along with a fuel tank before fitting the connectorto the tank; and

[0067]FIG. 24 is a vertical cross-sectional view of the conventionalconnector along with the tank after fitting the connector to the tank.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0068] Now, preferred embodiments of the fuel tank connector A accordingto the present invention will now be described with reference to theaccompanying drawings, wherein like reference numerals designatecorresponding or identical elements throughout the various drawings.

[0069] FIGS. 1-3 show the fuel tank connector A according to a firsttypical embodiment of the present invention. FIG. 1 is a verticalcross-sectional view of the fuel tank connector A according to thisembodiment along with the essential parts of a fuel tank B before theconnector has been fitted to the tank, and FIG. 2 is a top plan viewshowing how the fuel tank connector A is put on the tank B to be fittedto the tank.

[0070]FIG. 3 is a vertical cross-sectional view of the fuel tankconnector A along with the essential parts of the fuel tank B after theconnector has been fitted to the tank.

[0071] FIGS. 4-6 show the fuel tank connector A according to a secondtypical embodiment of the present invention. FIG. 4 is a verticalcross-sectional view of the fuel tank connector A according to thisembodiment along with the essential parts of a fuel tank B before theconnector has been fitted to the tank, and FIG. 5 is a top plan viewshowing how the fuel tank connector A is put on the tank B to be fittedto the tank.

[0072]FIG. 6 is a vertical cross-sectional view of the fuel tankconnector A along with the essential parts of the fuel tank B after theconnector has been fitted to the tank.

[0073] FIGS. 7-9 show the fuel tank connector A according to a thirdtypical embodiment of the present invention. FIG. 7 is a verticalcross-sectional view of the fuel tank connector A according to thisembodiment along with the essential parts of a fuel tank B before theconnector has been fitted to the tank, and FIG. 8 is a top plan viewshowing how the fuel tank connector A is put on the tank B to be fittedto the tank.

[0074]FIG. 9 is a vertical cross-sectional view of the fuel tankconnector A along with the essential parts of the fuel tank B after theconnector has been fitted to the tank.

[0075] FIGS. 10-22 show the fuel tank connector A according to a fourthtypical embodiment of the present invention. FIGS. 10-12 show theconnector A from different views. FIG. 13 is a vertical cross-sectionalview of the connector A along with the essential parts of a fuel tank Bbefore the connector A has been fitted to the tank B, and FIG. 14 is avertical cross-sectional view of the connector A along with theessential parts of the tank B after the connector has been fitted to thetank B. FIG. 15 shows in enlargement a portion of the connector A, whichis supposed to be melt-bonded to the tank B in fitting to the tank B.FIG. 16 shows the portion of the connector, which has been melt-bondedto the tank B. FIGS. 17, 19 and 21 show in enlargement a portion of theconnector to be melt-bonded to the fuel tank B in each of modified formsof the connector shown in FIGS. 10-16 in order to help understanding themodified forms. FIGS. 18, 20 and 22 show in enlargement the portion ofthe connector, which has been fitted to the fuel tank B, in each of themodified forms. (FIG. 18 shows how the modified form of FIG. 17 has beenmelt-bonded to the fuel tank B, FIG. 20 shows how the modified form ofFIG. 19 has been melt-bonded to the fuel tank B, and FIG. 22 shows howthe modified form of FIG. 21 has been melt-bonded to the fuel tank B.)

[0076] The fuel tank connector A according to each of the typicalembodiments is adapted to be fitted to an inner area Bc of an opening Baso as to cover the opening Ba formed in the fuel tank B to connect thefuel tank and a pipe C in communicating fashion. The connector comprisesa gas barrier member 10 made of a synthetic resin having a gas barrierproperty, the gas barrier member including a tubular portion 11 and aflanged portion 12 provided on a peripheral side of the tubular portion11 and having a greater side than the opening Ba of the fuel tank B. Thegas barrier member 10 is made of polybutylene terephthalate,polyphenylene sulfide, a liquid crystal polymer, aliphatic polyketone,aromatic polyamide, a blended polymer of an ethylene-vinyl alcoholcopolymer and high-density polyethylene, a blended polymer of polyamideand polyethylene, a blended polymer of polyamide and high-densitypolyethylene, or polyethylene terephthalate. This arrangement caneffectively minimize that evaporative emissions deriving from the fuelin the fuel tank leak from the connector.

[0077] The fuel tank connector A may be typically configured to havevarious required properties, such as fuel oil resistance. The connectoris fitted to the inner area Bc of various types of openings Ba formed inthe fuel tank B to connect the fuel tank B and various types of pipes C,such as a vent pipe and a fuel feeding pipe.

[0078] The fuel tank connector A may be used to connect any type of pipeC to the fuel tank B in such a state that the connector A is providedwith any type of valve, such as, a fuel cutoff valve 3, or is providedwith no valve.

[0079] The gas barrier member 10 forming the fuel tank connector A maybe made of polybutylene terephthalate, polyphenylene sulfide, a liquidcrystal polymer, aliphatic polyketone, aromatic polyamide, a blendedpolymer of an ethylene-vinyl alcohol copolymer and high-densitypolyethylene, a blended polymer of polyamide and polyethylene, a blendedpolymer of polyamide and high-density polyethylene, or polyethyleneterephthalate, which is suitable for use as a material of the fuel tankconnector A and is a material difficult to pass gas deriving from anytypes of fuel stored in the fuel tank B. Any one of the materials canprovide the connector A with a typical gas barrier function.

[0080] Any one of the synthetic materials, which can form the gasbarrier member 10 and has a gas barrier property, is difficult to passvarious types of gas deriving from fuel. The following fuel permeabilitytest, which was carried out to compare some of the synthetic materialswith high-density polyethylene under identical conditions, shows thatany one of the tested synthetic materials were significantly smallerthan the tested high-density polyethylene in fuel permeability amount,and that any one of the tested synthetic materials had a gas barrierproperty superior to the tested high-density polyethylene.

[0081] “Fuel Permeability Test”

[0082] Respective samples, which were made of the synthetic materialshaving a gas barrier property as listed above, and samples, which weremade of high-density polyethylene as stated, were prepared as samples tobe measured. Aluminum cups, which had a diameter of 38 mm, were preparedfor each of the samples.

[0083] As test chemicals, the following reagents were prepared:

[0084] (1) First reagent: Unleaded regular gasoline (corresponding toJIS K2202 No. 2)

[0085] (2) Second reagent: Mixed fuel of 90 vol. % of unleaded regulargasoline (corresponding to JIS K2202 No. 2) and 10 vol. % of ethanol

[0086] The first reagent of 4.6 g or the second reagent of 4.6 g was putin each of the aluminum cups. The respective samples to be measured wasfixedly put on the respective aluminum cups so that the respectivealuminum cups had their open ends closed with the respective samples tobe measured. The fuel permeability test (the fuel permeability testprescribed in JIS Z 0208-76), wherein the fuel permeation amount of apermeable area having 11.341 cm² was found by measuring a decrease inweight after lapse of 48 hours at a temperature of 60° C. in a gas phasemethod, shows the results in Table 1. TABLE 1 Synthetic resin SamplePermeation sample Reagent thickness amount Sample made of First 0.97 mm 6 mg aromatic polyamide reagent (AMODEL (trademark), 4.6 g AT5001;manufactured by Teijin Amoco Engineering Plastics Co., Ltd. Sample madeof First 0.98 mm  10 mg polybutylene reagent terephthalate 4.6 g(DURANEX (trademark) Second 0.98 mm  8 mg 2002; manufactured reagent byPolyplastics Co., Ltd.) 4.6 g Sample made of a First 0.93 mm 100 mgblended polymer of an reagent ethylene-vinyl alcohol 4.6 g copolymer andhigh- Second 0.93 mm  94 mg density polyethylene reagent (EVAL(trademark) XEP661; 4.6 g manufactured by Kuraray Co., Ltd.) Sample madeof a First 0.96 mm  0 mg blended polymer of reagent polyamide and high-4.6 g density polyethylene Second 0.96 mm  3 mg (MC8 (tradename);reagent manufactured by Toray 4.6 g Industries, Inc.) Sample made of aFirst 0.99 mm  0 mg blended polymer of reagent polyamide and high- 4.6 gdensity polyethylene Second 0.99 mm  14 mg (SP966 (tradename); reagentmanufactured by Toray 4.6 g Industries, Inc.) Sample made of high- First0.97 mm 780 mg density polyethylene reagent (KB145 (tradename); 4.6 gmanufactured by Second 0.97 mm 484 mg Nippon Polyolefin reagent Co.,Ltd. 4.6 g

[0087] The gas barrier member 10 includes the tubular portion 11 and theflanged portion 12 provided on the peripheral side of the tubularportion 11 and having a greater side than the opening Ba. The gasbarrier member may include another part helpful to the fuel tankconnector A, if necessary.

[0088] The connector A comprises a tubular unit 1 and a flange unit 2 toinclude the tubular portion 11 and the flanged portion 12 forming thegas barrier member 10. Another part, such as the fuel cutoff valve 3,may be provided at the tubular unit 1 or the flange unit 2, forming theconnector A.

[0089] The fuel tank B, to which the fuel tank connector A is fitted,may have any structure. For example, the fuel tank B may be constructedso that its entirety is made of a synthetic resin, or it has an outersurface around a peripheral edge Bb of the opening made of a syntheticresin capable of being melt-bonded to the connector A and the otherportion made of a suitable material, such as another synthetic resin ormetal.

[0090] The fuel tank connector A thus constructed may have a peripheralportion of the flanged portion melt-bonded to a synthetic resin Bdhaving a gas barrier property and forming the fuel tank B to be fittedto the fuel tank, thereby effectively minimize the leakage ofevaporative emissions from the fuel tank.

[0091] In the fuel tank connector A thus constructed, the gas barriermember 10 may have at least a portion of a surface, typically at least aportion except the inner side of the tubular portion 11, covered with anouter shell portion 50 a made of an olefin resin having an adhesiveproperty, allowing the gas barrier member 10 with the outer shellportion 50 a to be melt-bonded to the fuel tank B at the outer shell 50in reliable and easy fashion, in addition to the advantage statedearlier.

[0092] In the fuel tank connector A thus constructed, at least a portionof the outer shell portion 50 a, which is made of an olefin resin havingan adhesive property to cover at least a portion of the gas barriermember 10, and at least a portion of a surface of the gas barrier member10, which is uncovered with the outer shell portion 50 a, may be coveredwith an additional outer shell portion 50 b made of high-densitypolyethylene. Thus, the outer shell portion 50 b, which is made ofhigh-density polyethylene, can be fitted to the gas barrier member 10 ineasier and more reliable fashion, allowing the connector A to be fittedto the fuel tank B in more reliable and easier fashion, in addition tothe advantages stated earlier.

[0093] In the fuel tank connector A thus constructed, the leading end ofthe flanged portion 12 may be provided with an annular projected portion12 a, which projects toward the outer surface of the fuel tank B,increasing design freedom in fitting of the connector to the fuel tank Bin such a manner to effectively minimize the leakage of evaporativeemissions from the fuel tank B in addition to the advantages statedearlier.

[0094] The fuel tank connector A thus constructed may be used as aconnector for connection with a fuel feeding pipe to connect the fuelfeeding pipe to the fuel tank B in such a manner to effectively minimizethe leakage of evaporative emissions from fuel, in addition to theadvantages stated earlier.

[0095] The fuel tank connector A thus constructed may be used as aconnector for connection with a vent pipe to connect the vent pipe tothe fuel tank in such a manner to effectively minimize the leakage ofevaporative emissions from fuel, in addition to the advantages statedearlier.

[0096] The fuel tank connector A thus constructed may further comprisethe fuel cutoff valve 3 to connect a pipe C to the fuel tank B throughthe fuel cutoff valve, effectively minimizing the leakage of evaporativeemissions from fuel, in addition to the advantages stated earlier.

[0097] (1) Fuel Tank Connector A According to the First Embodiment

[0098] First, the fuel tank connector A according to the firstembodiment shown in FIGS. 1-3 will be specifically described.

[0099] The fuel tank connector A in the shown embodiment is configuredas an instrument to connect any type of pipe C to the fuel tank B, andis in particular a fuel tank connector A with the typical fuel cutoffvalve 3.

[0100] The fuel tank connector A in the shown embodiment is a connectorA adapted to be fitted to the inner area Bc of the opening Ba so as tocover, from outside, the opening Ba formed in the fuel tank B to connectthe fuel tank B and a pipe C in communicating fashion. The connector Aincludes the gas barrier member 10, which comprises the tubular portion11 and the flanged portion 12 provided on the peripheral side of thetubular portion 11 and having a greater side than the opening Ba of thefuel tank B, and which is made of a synthetic resin having a gas barrierproperty. The gas barrier member 10 is made of polybutyleneterephthalate, polyphenylene sulfide, a liquid crystal polymer,aliphatic polyketone, aromatic polyamide, a blended polymer of anethylenevinyl alcohol copolymer and high-density polyethylene, a blendedpolymer of polyamide and polyethylene, a blended polymer of polyamideand high-density polyethylene, or polyethylene terephthalate. In theshown embodiment, the gas barrier member 10 has at least a portion of asurface covered with the outer shell 50, more specifically, at least aportion of a surface covered with the outer shell portion 50 a made ofan olefin resin having an adhesive property. Additionally, at least aportion of the outer shell portion 50 a and at least a portion of thegas barrier member uncovered with the outer shell portion 50 a arecovered with the outer shell portion 50 b made of high-densitypolyethylene. The connector A can be melt-bonded to the fuel tank B atthe outer shell 50 to effectively minimize that evaporative emissionsderiving from the fuel in the fuel tank B leak from the connector.

[0101] The fuel tank connector A in the shown embodiment is used as aninstrument to connect any type of pipe C to the fuel tank B. In theshown embodiment, the connector A is provided with the typical fuelcutoff valve 3 and is fitted to an upper side of the fuel tank B as atypical example. The connector serves to feed, e.g., evaporativeemissions deriving from fuel to a charcoal canister or another deviceand to prevent the fuel from flowing out when the fuel level in the fueltank B changes.

[0102] In the fuel tank B, to which the connector A in the shownembodiment is fitted, at least a portion of the tank with the outershell 50 of the connector A melt-bonded thereto, i.e., an outer surfaceof the tank around the peripheral edge Bb of the opening in the fueltank B is made of a synthetic resin capable of being melt-bonded to theouter shell 50 and includes a gas barrier layer, i.e., a layer difficultto pass evaporative emissions from the fuel.

[0103] The fuel tank B typically includes an outer surface layer Be madeof a synthetic resin convenient for melt-bonding with the connector A,such as high-density polyethylene, and the gas barrier layer Bd made ofa synthetic resin layer to make it difficult to pass evaporativeemissions from the fuel. In the shown embodiment, the outer surfacelayer Be has a portion removed to provide a circumferential recessedportion Bf around the peripheral edge Bb of the opening so that the gasbarrier layer Bd having a gas barrier property is exposed at thecircumferential recessed portion.

[0104] The connector A in the shown embodiment includes the tubular unit1 with a bore 1 e, the flange unit 2 provided on a peripheral side ofthe tubular unit 1 and having a greater outer diameter than the openingBa, and the fuel cutoff valve 3. With a cylindrical portion 23 forming acylindrical body 20 of the fuel cutoff valve 3 inserted into the fueltank B through the opening Ba of the fuel tank B, the flange unit 2 ismelt-bonded to a surface of the fuel tank, which is made of a syntheticresin at least around the peripheral edge Bb of the opening. Thus, theconnector A is used for connecting the fuel tank B and a pipe C incommunicating fashion through the bore 1 e.

[0105] The opening Ba in the shown embodiment is formed in a circularshape, and the flange unit 2 is formed as circular plate, which has agreater diameter than the opening Ba.

[0106] The connector A in the shown embodiment specifically includes thetubular unit 1, which comprises a vertical tubular portion 1 aprojecting upwardly and a horizontal tubular portion 1 b connected to anupper end of the vertical tubular portion 1 a so as to be bent from thevertical tubular potion 1 a at right angles, and the flange unit 2 whichcomprises the circular plate projecting laterally from a periphery of alower end of the vertical tubular portion 1 a in the tubular unit 1. Theflange unit additionally includes the fuel cutoff valve 3, whichcomprises a disk-shaped portion 21 jutted downwardly from the flangeunit 2, i.e., in a direction away from the tubular unit 1, thecylindrical portion 23 extending downwardly from a peripheral edge ofthe disk-shaped portion 21, a lid 24 with an engagement projection 23 bengaged with an engagement slot 24 c formed in a lower edge of thecylindrical portion 23, a valve seat unit 30 provided in a recessedportion 22 in the disk-shaped portion 21 in communication with the bore1 e in the tubular unit 1, and a float 40 housed in a float chamber soas to be vertically movable in response to a change in the liquid levelof the liquid entering the float chamber, the float chamber comprisingthe disk-shaped portion 21 having the valve seat unit 30 with a valveseat 30 b, the cylindrical portion 23 and the lid 24. A valve body 40 a,which is provided on an upper end of the float 40, is configured to getin close contact with the valve seat 30 b in the valve seat unit 30 toclose the bore 1 e of the tubular unit 1 when the float 40 moves towardthe valve seat 30 b as the liquid level changes.

[0107] The gas barrier member 10 provided on the connector A is made ofa synthetic resin having a gas barrier property to avoid thetransmission of gas, typically evaporative emissions deriving from thefuel in the tank B, as much as possible. Examples of the synthetic resinare polybutylene terephthalate, polyphenylene sulfide, a liquid crystalpolymer, aliphatic polyketone, aromatic polyamide, a blended polymer ofan ethylene-vinyl alcohol copolymer and high-density polyethylene, ablended polymer of polyamide and polyethylene, a blended polymer ofpolyamide and high-density polyethylene, and polyethylene terephthalate.In the shown embodiment, the gas barrier member includes the tubularportion 11 with a passage 11 e forming the bore 1 e and the flangedportion 12 projecting laterally from the peripheral edge of the one endof the tubular portion 11.

[0108] The tubular portion 11 has an elbow-like shape, wherein avertical tubular portion 11 b is connected to a horizontal tubularportion 11 a at right angles. The flanged portion 12 is integrallyfitted to the vertical tubular portion 11 b so as to project laterallyfrom the peripheral portion of the lower end of the vertical tubularportion.

[0109] The flanged portion 12, which is provided on the peripheralportion of the vertical tubular portion 11 b, is configured to have agreater side than the opening Ba in the fuel tank B, i.e., the flangedportion 12 on the tubular portion 11 is configured to laterally extendfrom the peripheral portion of the tubular portion 11 toward theperipheral edge Bb of the opening in the fuel tank B. Specifically, theflanged portion 12 is formed as a circular plate, which has a greaterdiameter than the opening Ba in a circular shape.

[0110] The annular projected portion 12 a extends in a bent formdownwardly from a side of the flanged portion 12 facing the outersurface of the fuel tank B, i.e., a peripheral edge of the flangedportion 12 remote from the projected tubular portion 11, or toward thefuel tank B.

[0111] The fuel cutoff valve 3 is integrally fitted to a lower side ofthe gas barrier member thus constructed, which is located on a sideremote from the projected tubular portion 11.

[0112] The fuel cutoff valve 3 includes the cylindrical body 20 havingan upper side integrally provided with the disk-shaped portion 21 andintegrally fitted to the gas barrier member 10, the valve seat unit 30integrally fitted to the disk-shaped portion 21 in the cylindrical body20, the lid 24 fitted to a lower end of the cylindrical portion to closethe bottom opening of the cylindrical body 20, and the float 40 housedin the float chamber provided in the cylindrical body 20 closed by thelid 24 for opening and closing the valve seat 30 b in the valve seatunit 30, following a change in the fuel liquid level.

[0113] The cylindrical body 20 forming the fuel cutoff valve 3 includesthe disk-shaped portion 21 and the cylindrical portion 23 integrallyprojected from the disk-shaped portion 21, and the cylindrical body ismade of any type of synthetic resin, typically, a synthetic resin havinga gas barrier property, such as polyacetal.

[0114] The disk-shaped portion 21 forming the cylindrical body 20 has awall with a cavity 21 a therein, which communicates with outside toaccept the entry of a resin in molding. The disk-shaped portion also hasa peripheral edge integrally provided with the cylindrical portion 23,which extends downwardly. Additionally, the disk-shaped portion 21 has asubstantially central portion formed with the recessed portion 22, whichcommunicates with the passage 11 e in the tubular portion 11 and formsan opening 11 c of the tubular portion 11.

[0115] The recessed portion 22 formed in the disk-shaped portion 21communicates with the passage 11 e in the tubular portion 11 and has alarger diameter than the passage 11 e. In the shown embodiment, therecessed portion comprises a large diameter of stepped hole 22 a formedin a lower end of the disk-shaped portion 21 so as to be upwardlyrecessed, a conical hole 22 b extending from an upper end of the steppedhole 22 a toward the tubular portion 11, and another stepped hole 22 cextending from the conical hole 22 b to the tubular portion 11.

[0116] The cylindrical portion 23 is formed as a cylindrical andopen-bottomed body, which projects from the disk-shaped portion 21 asone unit. The cylindrical portion has an outer portion on a leading sideas a lower edge formed with the engagement projection 23 b forengagement with the lid 24 and a peripheral wall formed with a pluralityof holes 23 a. The cylindrical portion 23 has an inner wall formed witha plurality of guide ribs 23 c, which extend from a lower portion towardthe disk-shaped portion 21.

[0117] The holes 23 a formed in the cylindrical portion 23 serve tosmoothly move gas or another fluid between the inner space in the fueltank B and the inner space in the cylindrical portion 23, which housesthe float 40 therein and is closed by the lid 24.

[0118] The cylindrical body 20 thus constructed and the gas barriermember 10 are integrally fitted by, e.g., inserting the cylindrical body20 in a mold, injecting a synthetic resin for molding the gas barriermember 10 into the mold by injection or anther way, and molding the gasbarrier member 10 so as to cover a peripheral portion of the disk-shapedportion 21 in the cylindrical body 20 and a side of the disk-shapedportion 21 remote from the projected cylindrical portion 23 with thesynthetic resin as well as filling the synthetic resin into the cavity21 a in the cylindrical body 21.

[0119] In the shown embodiment, the gas barrier member 10 is integrallyfitted to the cylindrical body 20 so that the gas barrier memberincludes the flanged portion 12 covering the side of the disk-shapedportion remote from the projected cylindrical portion 23 and laterallyprojecting from the side, a covering portion 12 b projecting from alower side of the flanged portion 12 so as to cover the peripheralportion of the disk-shaped portion 21, the tubular portion 11 having thepassage 11 e in communication with the stepped hole 22 c in thedisk-shaped portion 21 and upwardly projecting from the upper side ofthe flanged portion 12, and the annular projected portion 12 downwardlyextending from the leading end of the disk-shaped portion 12 in a bentform.

[0120] In the shown embodiment, the outer surface of the gas barriermember 10, which is integrally fitted to the cylindrical body, iscovered by the outer shell 50, which extends on an outer surface of thecovering portion 12 b and a portion of the outer surface of the gasbarrier member 10 from the outer surface of the covering portion to anopen end 11 d through the leading edge of the annular projected portion12 a.

[0121] The outer shell 50 to be provided on the gas barrier member 10can be formed on the surface of the gas barrier member 10 by plasticsmolding wherein the cylindrical body 20 with the gas barrier member 10integrally fitted thereto is inserted into a mold, for instance.

[0122] The outer shell 50, which is provided so as to cover the surfaceof the gas barrier member 10, can be molded integrally with the gasbarrier member 10. The outer shell is made of a synthetic resin capableof being melt-bonded to the fuel tank B. In the shown embodiment, theouter shell has a layered structure, wherein the outer shell integrallyincludes the outer shell portion 50 a, which is made of an olefin resinhaving an adhesive property, and which covers the outer surface of thecovering portion 12 b and a portion of the outer surface of the gasbarrier member 10 from the outer surface of the covering portion to amiddle portion of the vertical tubular portion 11 b through the leadingedge of the annular projected portion 12 a, and the outer shell portion50 b, which is made of high-density polyethylene, and which covers aperipheral surface of the outer shell portion 50 a continuous to asurface of the outer shell portion 50 a facing the fuel tank B, and asurface from the peripheral surface to the open end 11 d of the tubularportion 11, i.e., the surfaces formed by the outer shell portion 50 amade of an olefin resin having an adhesive property and the gas barriermember 10.

[0123] In other words, in the shown embodiment, the flange unit 2 andthe tubular unit 1 of the connector A are provided so that the outershell 50 is integrally fitted to the flanged portion 12 and the tubularportion 11 in the gas barrier member 10. The flange portion 2 has theleading edge formed with an annular projection 2 a, which comprises theannular projected portion 12 a and the outer shell 50 covering theannular projected portion 12 a.

[0124] The valve seat unit 30, which is arranged in the recessed portion22 of the disk-shaped portion 21 in the cylindrical body 20 to providethe fuel cutoff valve 3 with the valve seat 30 b, is made of a syntheticresin adapted to melt-bonding to the disk-shaped portion 21 andcooperating with the disk-shaped portion 21 to provide the connector Awith a gas barrier function, i.e., any type of synthetic resin having agas barrier property to effectively avoid the transmission ofevaporative emissions deriving from the fuel, such as polyacetal. Thevalve seat unit has such a form that the valve seat 30 b, which receivesthe valve body 40 a of the float 40 to be closed, is provided on theedge of an aperture 30 a vertically passing through the valve seat 30 band is incorporated into the recessed portion 22.

[0125] Specifically, the valve seat body 30 has the aperture 30 a formedin a substantially central portion to vertically pass therethrough andcommunicate with the bore 1 e or the passage 11 e. The aperture 30 a hasa central portion formed with a restricted orifice 30 a′ and a portionbelow the restricted orifice 30 a′ formed with the conical valve seat 30b gradually expanding toward a lower edge of the aperture 30 a. Thevalve seat body 30 has an upper end formed with an annular groove 30 cto surround the aperture 30 a. The annular groove 30 c provides acylindrical part 30 d to an upper central portion of the valve seat body30. The outer wall of the annular groove 30 c forming the cylindricalpart 30 d comprises an upper disk part 30 e and a lower disk part 30 fprovided below the upper disk part 30 e and having a greater diameterthan the upper disk part 30 e. The valve seat body 30 is melt-bonded andintegrally fitted to the disk-shaped portion 21 so that the upper diskpart 30 e has an upper end pressed against the conical hole 22 b with anannular seal 31 fitted to the outer peripheral surface of the upper diskpart 30 e, and so that the lower disk part 30 f is housed in the largerdiameter of stepped hole 22 a at the lowest position so as to put theupper end of the lower disk part 30 f into close contact with the upperend of the larger diameter of stepped hole 22 a.

[0126] The float 40, which is incorporated in the cylindrical body 20thus constructed, is made of, e.g., polyacetal and is guided by theguide ribs 23 c in the cylindrical portion 23 to be vertically movablein smooth fashion, following a change in the fuel liquid level.

[0127] The float has the upper end formed with the valve body 40 a toget in close contact with the valve seat 30 b to close the aperture 30 ain the valve seat body 30 when the float is moved toward the valve seat30 b by a change in the fuel liquid level. The float has a substantiallycentral portion on a lower side formed with a recess 40 b upwardlyextending, and the recess 40 b includes an annular recess 40 b′ furtherupwardly extending and a circular base 40 c. The float includes a hole40 d formed therein to communicate between the recess 40 b and the upperend of the float.

[0128] The lid 24, which keeps the float 40 forming the fuel cutoffvalve 3 incorporated in the cylindrical portion 23, includes acylindrical peripheral wall 24 b, which upwardly extends from aperipheral edge of a bottom wall 24 a in a circular plate shape. Thecylindrical peripheral wall 24 b receives the cylindrical portion 23 soas to get the leading edge of the cylindrical portion 23 in contact withthe bottom wall 24 a, and the cylindrical portion 23 has the engagementprojection 23 b thereon engaged with an edge of the engagement slot 24 cin the cylindrical peripheral wall 24 b to assemble the lid to thecylindrical portion 23. The lid 24 has a substantially central portionon an inner side formed with a circular base 24 d, and a helicalcompression spring 41 is disposed on the circular base 24 d of the lidand the circular base 24 c of the float 40 to assemble the float 40 tothe cylindrical portion 23 so that the float is easily movable infloating fashion in the cylindrical portion, following a change in thefuel liquid level.

[0129] The lid 24, which assembles the float 40 into the cylindricalportion 23, has the bottom wall 24 a formed with a plurality ofapertures 24 e, which vertically pass through the bottom wall 24 a,allowing fuel or gas to easily flow into and out of the cylindricalportion 23.

[0130] When the float 40 does not receive the buoyancy from the fuelliquid, the helical compression spring 41 balances with the weight ofthe float 40 and elastically supports the float 40 so as to maintain thevalve body 40 a in a position away from the valve seat 30 b. When thefloat 40 receives the buoyancy from the fuel liquid, the helicalcompression spring allows the float 40 to float up easily and moveupwardly by the buoyancy. In the latter case, the helical compressionspring causes the float 40 to press its valve body 40 a into contactwith the valve seat 30 b against the buoyancy, e.g., if the vehicle withthe fuel tank turns over.

[0131] In the connector A, which includes the tubular unit 1 and theflange unit 2 comprising the outer shell 50 and the gas barrier member10 thus constructed and also includes the fuel cutoff valve 3, the valveseat unit 30 is integrally melt-bonded and fitted to the disk-shapedportion 21 forming the fuel cutoff valve 3. The cylindrical portion 23has the float 40 housed therein and the lid 24 fitted to the open bottomthereof with the helical compression spring 41 interposed between thehoused float 40 and the lid.

[0132] In the shown embodiment, the connector A thus constructed has theside of the cylindrical portion 23 inserted into the fuel tank B throughthe opening Ba formed in the upper side of the fuel tank B. The annularprojected portion 12 a of the gas barrier member 10 in the connector Ais melt-bonded to the synthetic resin Bd having a gas barrier propertyexposed in the circumferential recessed portion Bf formed in the fueltank B. The annular projected portion 2 a is housed in thecircumferential recessed portion Bf so as to be melt-bonded to the fueltank B. The annular projected portion 12 a is melt-bonded to thesynthetic resin Bd having a gas barrier property, and the outer shell 50has the annular projected portion 2 a melt-bonded to the fuel tank B.

[0133] By fitting the connector A to the inner area Bc of the openingformed in the fuel tank B as explained, the gas barrier member 10 caneffectively decrease the leakage of evaporative emissions deriving fromthe fuel from the fuel tank B.

[0134] The connector A can be easily and reliably fitted to the fueltank B since fitting the connector A to the fuel tank B is carried outby melt-bonding the connector A to the fuel tank B.

[0135] The leakage of the gas from the fuel tank B can be furthereffectively decreased since the connector A is fitted to the fuel tank Bby melt-bonding the gas barrier member 10 in the connector A to thesynthetic resin Bd having a gas barrier property in the fuel tank B.

[0136] The connector A, which has been fitted to the fuel tank B asexplained, may be used for connection with a suitable pipe C.

[0137] In order to that the connector A can easily and reliably maintainthe connection with the pipe C, the tubular unit 1 of the connector hasan outer peripheral surface of the horizontal tubular portion 1 b formedwith a plurality of ridges, which comprise conical guides 1 c having adiameter gradually reduced toward the open end of the tubular unit andvertical stepped surfaces 1 d extending from respective edges of theconical guides remote from the open end to the outer peripheral surfaceof the horizontal tubular portion 1 b, in the shown embodiment.

[0138] (2) Fuel Tank Connector A According to the Second Embodiment

[0139] Next, the fuel tank connector A according to the secondembodiment shown in FIGS. 4-6 will be specifically described.

[0140] The fuel tank connector A in the shown embodiment is configuredas an instrument to connect any type of pipe C to the fuel tank B, andis in particular a fuel tank connector A with the typical fuel cutoffvalve 3, which is fitted to the upper side of the fuel tank B.

[0141] The fuel tank connector A in the shown embodiment is a connectorA adapted to be fitted to the inner area Bc of the opening Ba so as tocover, from outside, the opening Ba formed in the fuel tank B to connectthe fuel tank B and a pipe C in communicating fashion. The connector Aincludes the gas barrier member 10, which comprises the tubular portion11 and the flanged portion 12 provided on the peripheral side of thetubular portion 11 and having a greater side than the opening Ba of thefuel tank B, and which is made of a synthetic resin having a gas barrierproperty. The gas barrier member 10 is made of polybutyleneterephthalate, polyphenylene sulfide, a liquid crystal polymer,aliphatic polyketone, aromatic polyamide, a blended polymer of anethylenevinyl alcohol copolymer and high-density polyethylene, a blendedpolymer of polyamide and polyethylene, a blended polymer of polyamideand high-density polyethylene, or polyethylene terephthalate. In theshown embodiment, the gas barrier member 10 has at least a portion of asurface covered with the outer shell 50, more specifically, at least aportion of a surface covered with an outer shell portion 50 a made of anolefin resin having an adhesive property. The connector A can bemelt-bonded to the fuel tank B at the outer shell 50 to effectivelyminimize that evaporative emissions deriving from the fuel in the fueltank B leak from the connector.

[0142] The fuel tank connector A according to the second embodiment asthe same structure or substantially the same structure as the fuel tankconnector A according to the first embodiment except that the outershell 50 is made of a single layer of adhesive olefin resin and isprovided on the gas barrier member 10 forming the fuel tank connector Aaccording to the second embodiment. The connector according to thesecond embodiment can be fitted to the fuel tank A by the same method asthe connector according to the first embodiment.

[0143] Parts identical to or substantially identical to the parts of thefuel tank connector A according to the first embodiment are designatedby like reference numerals, and explanation on these parts will beomitted.

[0144] In the fuel tank connector A according to the second embodiment,the outer shell 50, which is supposed to be the gas barrier member 10,may be provided on the gas barrier member 10 by, e.g., plastics molding,wherein the cylindrical body 20 with the gas barrier member 10integrally provided thereto is inserted into a mold as in thepreparation for the fuel tank connector A according to the firstembodiment.

[0145] The outer shell 50, which is provided so as to cover the surfaceof the gas barrier member 10, can be molded integrally with the gasbarrier member 10. The outer shell is made of a synthetic resin capableof being melt-bonded to the fuel tank B. In the shown embodiment, theouter shell includes the outer shell portion 50 a, which is made of anolefin resin having an adhesive property, and which covers the outersurface of the covering portion 12 b and a portion of the outer surfaceof the gas barrier member 10 from the outer surface of the coveringportion to the open end 11 d of the tubular portion 11 through theleading edge of the annular projected portion 12 a so as to be integralwith the gas barrier member 10.

[0146] In the shown embodiment, the connector A thus constructed has theside of the cylindrical portion 23 inserted into the fuel tank B throughthe opening Ba formed in the upper side of the fuel tank B. The annularprojected portion 12 a of the bas barrier member 10 in the connector Ais melt-bonded to the synthetic resin Bd having a gas barrier propertyexposed in the circumferential recessed portion Bf formed in the fueltank B. The annular projected portion 2 a is housed in thecircumferential recessed portion Bf and is melt-bonded to the fuel tankB. The annular projected portion 12 a is melt-bonded to the syntheticresin Bd having a gas barrier property, and the outer shell 50 has theannular projected portion 2 a melt-bonded to the fuel tank B.

[0147] By fitting the connector A to the inner area Bc of the openingformed in the fuel tank B as explained, the gas barrier member 10 caneffectively decrease the leakage of evaporative emissions deriving fromthe fuel from the fuel tank B.

[0148] The connector A can be easily and reliably fitted to the fueltank B since fitting the connector A to the fuel tank B is carried outby melt-bonding the connector A to the fuel tank B.

[0149] The leakage of the gas from the fuel tank B can be furthereffectively decreased since the connector A is fitted to the fuel tank Bby melt-bonding the gas barrier member 10 in the connector A to thesynthetic resin Bd having a gas barrier property in the fuel tank B.

[0150] (3) Fuel Tank Connector A According to the Third Embodiment

[0151] First, the fuel tank connector A according to the thirdembodiment shown in FIGS. 7-9 will be specifically described.

[0152] The fuel tank connector A in the shown embodiment is configuredas an instrument to connect any type of pipe C to a fuel tank B, and isin particular a fuel tank connector A with the typical fuel cutoff valve3.

[0153] The fuel tank connector A in the shown embodiment is a connectorA adapted to be fitted to the inner area Bc of the opening Ba so as tocover, from outside, the opening Ba formed in the fuel tank B to connectthe fuel tank B and a pipe C in communicating fashion. The connector Aincludes the gas barrier member 10, which comprises the tubular portion11 and the flanged portion 12 provided on a peripheral side of thetubular portion 11 and having a greater side than the opening Ba of thefuel tank B, and which is made of a synthetic resin having a gas barrierproperty. The gas barrier member 10 is made of polybutyleneterephthalate, polyphenylene sulfide, a liquid crystal polymer,aliphatic polyketone, aromatic polyamide, a blended polymer of anethylenevinyl alcohol copolymer and high-density polyethylene, a blendedpolymer of polyamide and polyethylene, a blended polymer of polyamideand high-density polyethylene, or polyethylene terephthalate. In theshown embodiment, the gas barrier member 10 has at least a portion of asurface covered with the outer shell 50, more specifically, s sidefacing the fuel tank B integrally fitted with an outer shell portion 50c made of a modified polyolefin resin having an adhesive property. Theconnector A can be melt-bonded to the fuel tank B at the outer shellportion 50 c to effectively minimize that evaporative emissions derivingfrom the fuel in the fuel tank B leak from the connector.

[0154] The fuel tank connector A in the shown embodiment is used as aninstrument to connect any type of pipe C to the fuel tank B. In theshown embodiment, the connector A is provided with the typical fuelcutoff valve 3 and is fitted to the upper side of the fuel tank B as atypical example. The connector serves to feed, e.g., evaporativeemissions deriving from fuel to a charcoal canister or another deviceand to prevent the fuel from flowing out when the fuel level in the fueltank B changes.

[0155] In the fuel tank B, to which the connector A in the shownembodiment is fitted, at least a portion of the tank with the connectorA melt-bonded thereto, i.e., an outer surface of the tank around theperipheral edge Bb of the opening in the fuel tank B is made of asynthetic resin capable of being melt-bonded to an outer shell 50 andincludes a gas barrier layer, i.e., a layer difficult to passevaporative emissions from the fuel.

[0156] The fuel tank B typically includes the outer surface layer Bemade of a synthetic resin convenient for melt-bonding with the connectorA, such as polyethylene and high-density polyethylene, and the gasbarrier layer Bd made of a synthetic resin layer to make it difficult topass evaporative emissions from the fuel. In the shown embodiment, theouter surface layer Be has a portion removed to provide thecircumferential recessed portion Bf around the peripheral edge Bb of theopening so that the gas barrier layer Bd having a gas barrier propertyis exposed at the circumferential recessed portion.

[0157] In the shown embodiment, the gas barrier member 10, which formsthe connector A fitted to the fuel tank B, includes the tubular portion11 and the flanged portion 12 provided on the peripheral side of thetubular portion 11 and having a greater side than the opening Ba of thefuel tank B. The gas barrier member also includes a cylindrical portion23 forming the fuel cutoff valve 3 and having a relatively largediameter. The gas barrier member 10 is made of polybutyleneterephthalate, polyphenylene sulfide, a liquid crystal polymer,aliphatic polyketone, aromatic polyamide, a blended polymer of anethylene-vinyl alcohol copolymer and high-density polyethylene, ablended polymer of polyamide and polyethylene, a blended polymer ofpolyamide and high-density polyethylene, or polyethylene terephthalate.

[0158] The tubular portion 11 forming the gas barrier member 10 in theshown embodiment includes a vertical tubular portion 11 b verticallyprojecting from the flanged portion 12 and a horizontal tubular portion11 a rectangularly connected to the vertical tubular portion 11 b atright angles. The tubular portion also includes a tubular projectedportion 11 f, which downwardly projects from the flanged portion 12 andcommunicates with the vertical tubular portion 11 b. The tubularprojected portion 11 f has a lower edge formed with a valve seat 11 f′as a recessed portion provided at a lower end of a passage 11 e in thetubular portion.

[0159] The flanged portion 12, which is provided on a peripheral portionof the vertical tubular portion 11 a, is configured to have a greaterside than the opening Ba formed in the fuel tank B. In other words, theflanged portion 12 provided on the tubular portion 11 is provided so asto extend from the peripheral portion of the tubular portion 11 toward alateral portion of the peripheral edge Bb of the opening formed in thefuel tank B. More specifically, the flanged portion 12 is formed in acircular plate shape, and the flanged portion 12 is configured to have agreater diameter than the opening Ba formed in a circular shape.

[0160] The flanged portion 12 thus constructed has an outer peripheraledge on a side facing the outer surface of the fuel tank B, i.e., on aprojecting side of the projected tubular portion 11 f, formed with anannular projected portion 12 a′, which projects in a bent shapedownwardly, i.e., toward the fuel tank B.

[0161] The gas barrier member 10 thus constructed has a lower side,i.e., the projecting side of the projected tubular portion 11 f, formedintegrally with the cylindrical portion 23 forming the fuel cutoffvalve.

[0162] The cylindrical portion 23 forming the fuel cutoff valve 3 isformed an open-bottomed cylindrical body, which is formed integrallywith the flanged portion 12 so as to project downwardly from the lowerside of the flanged portion 12 and to surround the tubular projectedportion 11 f. The cylindrical portion has an outer portion on a leadingside as a lower edge formed with an engagement projection 23 b forengagement with a lid 24. The cylindrical portion has a peripheral wallformed with a plurality of apertures 23 a. The cylindrical portion 23has an inner wall formed with a plurality of guide ribs 23 c, whichextend from a lower portion toward the flanged portion 12.

[0163] The apertures 23 a formed in the cylindrical portion 23 providesa structure wherein gas or other fluid can smoothly move between theinner space of the fuel tank B and the inner space of the cylindricalportion 23, which has the float 40 housed therein and is closed by thelid 24.

[0164] The outer shell 50 is integrally fitted to the gas barrier member10 so as to be continuously fitted to an upper peripheral surface of thecylindrical portion 23 in the gas barrier member 10, a surface of theflanged portion 12 continuous to the upper peripheral surface, and aninner surface of the annular projected portion 12 a′ continuous to thesurface of the flanged portion 12. The connector A can be melt-bondedand fitted to the fuel tank B by use of the outer shell 50.

[0165] The outer shell 50 in the shown example is integrally providedwith a cylindrical part 53 fitted to the upper peripheral surface of thecylindrical portion 23, a flange part 52 fitted to a lower side of theflanged portion 12, and a projected part 54 fitted to the inner surfaceof the annular projected portion 12 a′ and projecting further downwardlythan the annular projected portion 12 a′. When the projected part 54 hasa leading end melt-bonded to the circumferential recessed portion Bf ofthe fuel tank B, the annular projected portion 12 a′ has a leading endgotten in close contact with the outer surface of the fuel tank B.

[0166] The outer shell 50 forming the connector A may be fitted to thegas barrier member 10 by any one of various types of methods. Forexample, the outer shell can be integrally fitted to the gas barriermember 10 by, e.g., inserting the gas barrier member 10 in a mold andinjecting a synthetic resin into the mold.

[0167] For example, even if the gas barrier member 10 is made ofpolybutylene terephthalate having a superior gas barrier property, theouter shell 50 can be integrally fitted to the gas barrier member 10 inreliable fashion since the outer shell 50 is typically formed as theouter shell portion 50 c made of a modified polyolefin resin and havingan adhesive property. The connector A with the outer shell portion 50 ccan be fitted to the fuel tank B since the outer shell portion can beproperly melt-bonded to the synthetic resin of the fuel tank B, such aspolyethylene and high-density polyethylene.

[0168] The outer shell 50 can be also properly melt-bonded to thesynthetic resin Bd having a gas barrier property in the fuel tank B tofit the connector A to the fuel tank B since the outer shell 50 formingthe connector A is formed as the outer shell portion 50 c made of amodified polyolefin resin having an adhesive property as explained.

[0169] In the connector A including the outer shell 50 thus constructedand the gas barrier member 10, the tubular portion 11 in the gas barriermember 10 forms a tubular unit 1 of the connector A, and the outer shell50 and the gas barrier member 10 form a flange unit 2 of the connector Alaterally projecting from the tubular unit 1. The flange unit 2 has aprojecting edge provided with an annular projected portion 2 a′, whichprojects toward the fuel tank B and is formed from the annular projectedportion 12 a′ and the projected portion 54. In the shown embodiment, theflange portion 2 has a lower side provided with the typical fuel cutoffvalve 3.

[0170] The float 40 forming the fuel cutoff valve 3 is made of, e.g.,polyacetal. The float is housed in the cylindrical portion 23 so as tobe guided by the guide ribs 23 c and is vertically movable in smoothfashion, following a change in the fuel liquid level. The float has theupper end provided with the valve body 40 a, which gets in close contactwith the valve seat 11 f′ to close the passage 11 e in upper movement.The float has a substantially central portion on a lower side formedwith the recess 40 b extending upwardly. The recess 40 b has the annularrecess 40 b′ extending further upwardly. The recess 40 b also has thecircular base 40 c formed therein. The float also has the hole 40 dformed therein so as to communicate between the recess 40 b and theupper end of the float 40.

[0171] The lid 24, which keeps the float 40 forming the fuel cutoffvalve 3 in an incorporated state in the cylindrical portion 23, includesa cylindrical peripheral wall 24 b upwardly extending from a peripheraledge of a bottom wall 24 a formed in a circular plate. The cylindricalperipheral wall 24 b houses the cylindrical portion 23 so as to get aleading edge of the cylindrical portion 23 in touch with the bottom wall24 a. The lid is assembled to the cylindrical portion 23 by engaging theengagement projection 23 b formed on the cylindrical portion 23 with anedge of an engagement slot 24 c formed in the cylindrical peripheralwall 24 b. By a helical compression spring 41 disposed on a circularbase 24 d formed at a substantially central portion on an inner side ofthe lid 24 and on the circular base 40 c of the float 40, the float 40can float up so as to be easily movable in the cylindrical portion 23,following a change in fuel the liquid level.

[0172] The lid 24, which incorporates the float 40 into the cylindricalportion 23, has the bottom wall 24 a formed with a plurality ofapertures 24 e vertically passing therethrough, allowing fuel or gas toeasily flow into and out of the cylindrical portion 23.

[0173] When the float 40 does not receive the buoyancy from the fuelliquid, the helical compression spring 41 balances with the weight ofthe float 40 and elastically supports the float 40 so as to maintain thevalve body 40 a in a position away from the valve seat 11 f′. When thefloat 40 receives the buoyancy from the fuel liquid, the helicalcompression spring allows the float 40 to float up easily and moveupwardly by the buoyancy. In the latter case, the helical compressionspring causes the float 40 to press its valve body 40 a into contactwith the valve seat 11 f′ against the buoyancy, e.g., if the vehiclewith the fuel tank turns over.

[0174] In the connector A, which includes the tubular unit 1 and theflange unit 2 comprising the outer shell 50 and the gas barrier member10 thus constructed and also includes the fuel cutoff valve 3, thecylindrical portion 23 has the float 40 housed therein and the lid 24fitted to the open bottom thereof with the helical compression spring 41interposed between the housed float 40 and the lid.

[0175] The connector A thus constructed includes the tubular unit 1 withthe passage 11 e, the flange unit 2 provided on the peripheral portionof the tubular unit 1 and having a greater side than the opening Ba, andthe fuel cutoff valve 3. With the cylindrical portion 23 of the fuelcutoff valve 3 inserted into the fuel tank B through the opening Ba ofthe fuel tank B, the flange unit 2 is melt-bonded to a surface of thefuel tank, which is made of a synthetic resin at least around theperipheral edge Bb of the opening. Thus, the connector A is used forconnecting the fuel tank B and a pipe C in communicating fashion throughthe passage 11 e.

[0176] The opening Ba in the shown embodiment is formed as a circularopening, and the flange unit 2 is formed in a circular plate shape andhas a greater diameter than the opening Ba.

[0177] The connector A in the shown example includes the tubular portion1, which specifically comprises the vertically tubular portion 11 bprojecting upwardly, the horizontal tubular portion 11 a connected to anupper end of the vertical tubular portion 11 b so as to be bent from thevertical tubular portion 11 b at right angles, and the tubular projectedportion 11 f forming the valve seat 11 f′. The connector also includesthe flange unit 2, which is formed in a circular plate shape andlaterally extends from a lower peripheral portion of the verticaltubular portion 11 b in the tubular unit 1. Additionally, the flangeunit includes the fuel cutoff valve 3. In other words, the connectorincludes the cylindrical portion 23 downwardly projecting from the lowerside of the flange unit 2, the lid 24 fitted by engaging the engagementslot 24 c with the engagement projection 23 b formed on a lower edge ofthe cylindrical portion 23, the tubular projected portion 11 fprojecting from the lower side of the flange unit 2 so as to communicatewith the vertical tubular portion 11 b and having the lower edge formedwith the recessed valve seat 11 f′, and the float 40 housed in a floatchamber formed by the flange unit 2 having the tubular projected portion11 f with the valve seat 11 f′, the cylindrical portion 23 and the lid24 so as to be vertically movable in response to a change in the liquidlevel of a liquid entering the float chamber. The float 40 has the upperside formed with the valve body 40 a, which gets in contact with thevalve seat 11 f′ in the tubular projected portion 11 f to close thepassage 11 e in the tubular portion 1, following upward movement of thefloat 40 caused by a change in the fuel liquid level.

[0178] The connector A thus constructed has the side of the cylindricalportion 23 inserted into the fuel tank B through the opening Ba formedin the upper side of the fuel tank B. While the annular projectedportion 12 a′ of the gas barrier member 10 in the annular projectedportion 2 a′ is caused to abut against the outer surface of the fueltank B, the projected portion 54, which comprises the outer shell 50 inthe annular projected portion 2 a′ to be housed in the circumferentialrecessed portion Bf formed in the fuel tank B, has a leading edgemelt-bonded to the surface of the circumferential recessed portion Bf tofit the connector to the fuel tank B.

[0179] By fitting the connector A to the inner area Bc of the openingformed in the fuel tank B as explained, the gas barrier member 10 caneffectively decrease the leakage of evaporative emissions deriving fromthe fuel from the fuel tank B since the annular projected portion 12 a′formed by the gas barrier member 10 is gotten in close contact with thesurface of the fuel tank B.

[0180] The gas barrier member 10 may be made of a synthetic resin havinga superior gas barrier property, such as polybutylene terephthalate,since the outer shell 50 is made of a modified polyolefin resin havingan adhesive property.

[0181] The connector A, which has been fitted to the fuel tank B asexplained, may be used for connection with a suitable pipe C.

[0182] In order to that the connector A can easily and reliably maintainthe connection with the pipe C, the tubular unit 1 of the connector hasan outer peripheral surface of the horizontal tubular portion 11 aformed with a plurality of ridges, which comprise conical guides 1 chaving a diameter gradually reduced toward the open end of the tubularunit and vertical stepped surfaces 1 d extending from respective edgesof the conical guides remote from the open end to the outer peripheralsurface of the horizontal tubular portion 11 a, in the shown embodiment.

[0183] (4) Fuel Tank Connector A According to the Fourth Embodiment

[0184] Next, the fuel tank connector A according to the fourthembodiment shown in FIGS. 10-18 will be specifically described.

[0185] The fuel tank connector A in the shown embodiment is configuredas an instrument to connect any type of pipe C to a fuel tank B, and isin particular a fuel tank connector A with the typical fuel cutoff valve3.

[0186] The fuel tank connector A in the shown embodiment is a connectorA adapted to be fitted to an inner area Bc of an opening Ba so as tocover, from outside, the opening Ba formed in the fuel tank B to connectthe fuel tank B and a pipe C in communicating fashion. The connector Aincludes the gas barrier member 10, which comprises the tubular portion11 and the flanged portion 12 provided on a peripheral side of thetubular portion 11 and having a greater side than the opening Ba of thefuel tank B, and which is made of a synthetic resin having a gas barrierproperty. The gas barrier member 10 is made of polybutyleneterephthalate, polyphenylene sulfide, a liquid crystal polymer,aliphatic polyketone, aromatic polyamide, a blended polymer of anethylene-vinyl alcohol copolymer and high-density polyethylene, ablended polymer of polyamide and polyethylene, a blended polymer ofpolyamide and high-density polyethylene, or polyethylene terephthalate.In the shown embodiment, the gas barrier member 10 has at least aportion of a surface covered with the outer shell 50, more specifically,at least a portion of a surface covered with an outer shell portion 50 dmade of polyethylene or high-density polyethylene. The connector A caneffectively minimize that evaporative emissions deriving from the fuelin the fuel tank B leak from the connector.

[0187] The fuel tank connector A in the shown embodiment is used as aninstrument to connect any type of pipe C to the fuel tank B. In theshown embodiment, the connector A is provided with the typical fuelcutoff valve 3 and is fitted to the upper side of the fuel tank B as atypical example. The connector serves to feed, e.g., evaporativeemissions deriving from fuel to a charcoal canister or another deviceand to prevent the fuel from flowing out when the fuel level in the fueltank B changes.

[0188] In the fuel tank B, to which the connector A in the shownembodiment is fitted, at least a portion of the tank with the outershell 50 of the connector A melt-bonded thereto, i.e., an outer surfaceof the tank around a peripheral edge Bb of the opening in the fuel tankB is made of a synthetic resin capable of being melt-bonded to the outershell 50 and includes a gas barrier layer, i.e., a layer difficult topass evaporative emissions from the fuel.

[0189] The fuel tank B typically includes an outer surface layer Be madeof a synthetic resin convenient for melt-bonding with the connector A,such as high-density polyethylene, and the gas barrier layer Bd made ofa synthetic resin layer to make it difficult to pass evaporativeemissions from the fuel.

[0190] The connector A in the shown embodiment includes the tubular unit1 with a bore 1 e, the flange unit 2 provided on a peripheral portion ofthe tubular unit 1 and having a greater side than the opening Ba, andthe fuel cutoff valve 3. With the cylindrical portion 23 of the fuelcutoff valve 3 inserted into the fuel tank B through the opening Ba ofthe fuel tank B, the flange unit 2 has a leading end melt-bonded to asurface of the fuel tank, which is made of a synthetic resin at leastaround the peripheral edge Bb of the opening. Thus, the connector A isused for connecting the fuel tank B and a pipe C in communicatingfashion through the bore 1 e.

[0191] The opening Ba in the shown embodiment is formed as a circularopening, and the flange unit 2 is formed in a circular plate shape andhas a greater diameter than the opening Ba.

[0192] More specifically, the connector A in the shown embodimentincludes the tubular unit 1, which comprises a vertical tubular portion1 a projecting upwardly and a horizontal tubular portion 1 b connectedto an upper end of the vertical tubular portion 1 a so as to be bentfrom the vertical tubular portion 1 a at right angles. The connectoralso includes the flange unit 2, which is formed in a circular plateshape and projects laterally from a lower outer peripheral portion ofthe vertical tubular portion 1 a in the tubular unit 1. The flange unitis provided with the fuel cutoff valve 3, which comprises thedisk-shaped portion 21 jutted downwardly from the flange unit 2 on alower side of the flange unit 2, i.e., on a side of the flange unitopposite to the tubular unit 1, the cylindrical portion 23 projectingdownwardly from a peripheral edge of the disk-shaped portion 21, the lid24 having the engagement slot 24 c engaged with the engagementprojection 23 b formed on a lower end of the cylindrical portion 23 tobe fitted to the cylindrical portion, and the valve seat unit 30provided in the recessed portion 22 of the disk-shaped portion 21 so asto communicate with the bore 1 e in the tubular unit 1. The fuel cutoffvalve also comprises the float chamber formed by the disk-shaped portion21 having the valve seat unit 30 with a valve seat 30 b, the cylindricalportion 23 and the lid 24, and the float 40 housed in the float chamberso as to be vertically movable in response to a change in the liquidlevel of a liquid entering into the float chamber. The float 40 has theupper side formed with the valve body 40 a, which gets in close contactwith the valve seat 30 b in the valve seat unit 30 to close the bore 1 ein the tubular unit 1 when the float 40 moves toward the valve seat 30b, following a change in the fuel liquid level.

[0193] The gas barrier member 10 provided on the connector A is made ofa synthetic resin having a gas barrier property to avoid thetransmission of gas, typically evaporative emissions deriving from thefuel in the tank B, as much as possible. Examples of the synthetic resinare polybutylene terephthalate, polyphenylene sulfide, a liquid crystalpolymer, aliphatic polyketone, aromatic polyamide, a blended polymer ofan ethylene-vinyl alcohol copolymer and high-density polyethylene, ablended polymer of polyamide and polyethylene, a blended polymer ofpolyamide and high-density polyethylene, and polyethylene terephthalate.In the shown embodiment, the gas barrier member includes the tubularportion 11 with a passage 11 e forming the bore 1 e and the flangeportion 12 projecting laterally from the peripheral edge of the one endof the tubular portion 11.

[0194] The tubular unit 11 includes a vertical tubular portion 11 b anda horizontal tubular portion 11 a connected to the vertical tubularportion 11 b at right angles, which provide an elbow-like shape. Thetubular portion 11 is integrally formed with the flanged portion 12,which projects laterally from the lower outer peripheral portion of thevertical tubular portion 11 b.

[0195] The flanged portion 12, which is provided on the outer peripheralportion of the vertical tubular portion 11 b, has a greater side thanthe opening Ba in the fuel tank B. In other words, the flanged portion12, which is provided on the tubular portion 11, extends from the outerperipheral portion of the tubular portion 11 toward a lateral side ofthe peripheral edge Bb of the opening in the fuel tank B. Specifically,the flanged portion 12 is formed in a circular plate-like shape, and theflanged portion 12 has a greater diameter than the opening Ba, which isformed in a circular shape.

[0196] The flanged portion 12 thus constructed has an annular projectedportion 12 a projected from an outer peripheral edge thereof on a sidethereon facing the fuel tank B, i.e., a side thereof opposite to theprojected tubular portion 11 so as to extend in a bent shape downwardly,i.e., toward the fuel tank B.

[0197] The gas barrier member 10 thus constructed has a lower side,i.e., a side opposite to the projected tubular portion 11, fittedintegrally with the fuel cutoff valve 3.

[0198] The fuel cutoff valve 3 includes the cylindrical body 20 havingthe upper end integrally provided with the disk-shaped portion 21 so asto be integral with the gas barrier member 10, the valve seat unit 30integrally fitted in the disk-shaped portion 21 of the cylindrical body20, and the lid 24 fitted to the lower end of the open-bottomedcylindrical portion 23 in the cylindrical body 20. The fuel cutoff valvealso includes the float 40, which is housed in the float chamberprovided in the cylindrical body closed by the lid 24, and which opensand closes the valve seat 30 b in the valve unit 30, following a changein the fuel liquid level.

[0199] The cylindrical body 20 forming the fuel cutoff valve 3 includesthe disk-shaped portion 21 and the cylindrical portion 23 integrallyprovided on the disk-shaped portion 21 so as to project therefrom. Thecylindrical body may be made of any type of synthetic resin, typically asynthetic resin having a gas barrier property, such as polyacetal.

[0200] The disk-shaped portion 21 forming the cylindrical unit 20 hasthe cavity 21 a formed therein so as to communicate with outside andaccept a molding resin. The disk-shaped portion has the cylindricalportion 23 integrally provided thereon to extend downwardly from theouter peripheral edge thereof. The disk-shaped portion 21 has asubstantially central portion formed with the recessed portion 22, whichcommunicate with the passage 11 e in the tubular portion 11 and form theopening 11 c of the tubular portion 11.

[0201] The recessed portion 22 formed in the disk-shaped portion 21communicates with the passage 11 e in the tubular portion 11 and has agreater diameter than the passage 11 e. In the shown embodiment, therecessed portion comprises the larger diameter of stepped hole 22 aformed in a lower portion of the disk-shaped portion 21 so as to extendupwardly, the conical hole 22 b extending from the upper end of thelarger diameter of stepped hole 22 a toward the tubular portion 11, andthe additional stepped hole 22 c extending from the conical hole 22 b tothe tubular portion 11.

[0202] The cylindrical portion 23 is formed as an open-bottomedcylindrical member, which projects from the disk-shaped portion 21 asbeing integral therewith. The cylindrical portion has the outer portionon the leading edge as the lower edge formed with the engagementprojection 23 b for engagement with the lid 24. The cylindrical portionhas the outer peripheral wall formed with the plural apertures 23 a andthe inner wall formed with the plural guide ribs 23 c so as to extendfrom a lower portion of the inner wall of the cylindrical portion towardthe disk-shaped portion 21.

[0203] The apertures 23 a formed in the cylindrical portion 23 provide astructure wherein fluid, such as gas, can smoothly move between theinner space of the fuel tank B and the inner space in the cylindricalportion 23, which houses the float 40 therein and is closed by the lid24.

[0204] The cylindrical body 20 thus constructed and the gas barriermember 10 are integrally fitted by, e.g., inserting the cylindrical body20 in a mold, injecting a synthetic resin for molding the gas barriermember 10 into the mold by injection or anther way, and molding the gasbarrier member 10 so as to cover a peripheral portion of the disk-shapedportion 21 in the cylindrical body 20 and a side of the disk-shapedportion 21 remote from the projected cylindrical portion 23 with thesynthetic resin as well as filling the synthetic resin into the cavity21 a in the cylindrical body 21.

[0205] In the shown embodiment, the gas barrier member 10 is integrallyfitted to the cylindrical body 20 so as to include the flanged portion12 covering a side of the disk-shaped portion 21 opposite to thecylindrical portion 23 and projecting laterally from the side, thecovering portion 12 b projecting from a lower side of the flangedportion 12 so as to cover a circumferential surface of the disk-shapedportion 21, the tubular portion 11 projecting upwardly from an upperside of the flanged portion 12 so as to have the passage 11 e incommunication with the additional stepped hole 22 c in the disk-shapedportion 21, and the annular projected portion 12 a extending downwardlyfrom a leading edge of the flanged portion 12 so as to have a bentshape.

[0206] The gas barrier member 10, which is integrally fitted to thecylindrical body, has an outer surface thereof, i.e., an outer surfacethereof from the outer surface of the annular projected portion 12 a tothe open end 11 d of the tubular portion 11 in the shown embodiment,covered by the outer shell 50, which made of polyethylene orhigh-density polyethylene.

[0207] The outer shell 50 to be provided on the gas barrier member 10can be formed on the surface of the gas barrier member 10 by plasticsmolding, wherein the cylindrical body 20 with the gas barrier member 10integrally fitted thereto is inserted into a mold, for instance.

[0208] In the shown embodiment, the flange unit 2 and the tubular unit 1of the connector A is formed so that the outer shell 50 is integrallyfitted to the flanged portion 12 and the tubular portion 11 in the gasbarrier member 10. The flange unit 2 has a leading edge provided with anannular projected portion 51, which is formed by the annular projectedportion 12 a and the outer shell 50 covering the annular projectedportion 12 a.

[0209] When the gas barrier member 10 of the connector A is made of ablended polymer of polyamide and polyethylene or a blended polymer ofpolyamide and high-density polyethylene, the integration between the gasbarrier member 10 and the outer shell 50 made of polyethylene orhigh-density polyethylene becomes better. In this case, the connectorcan be conveniently melt-bonded to the fuel tank B as well.

[0210] The valve seat unit, which is provided in the recessed portion 22of the disk-shaped portion 21 in the cylindrical unit 20 and providesthe valve seat 30 b of the fuel cutoff valve 3, is made of a syntheticresin providing a gas barrier function to the connector A together withthe disk-shaped portion 21, i.e., any type of synthetic resin having agas barrier property capable of effectively avoiding the transmission ofevaporative emissions from the fuel, such as polyacetal. The valve seatunit has such a structure wherein the valve seat 30 b, which receivesthe valve body 40 a of the float 40 to be closed, is provided on theedge of the aperture 30 a vertically passing through the valve seatunit. The valve seat unit can be incorporated in the recessed portion22.

[0211] In other words, the valve seat unit 30 has the aperture 30 aformed in a substantially central portion so as to vertically passtherethrough in communication with the bore 1 e (11 e). The aperture 30a comprises the smaller diameter of orifice 30 a′ at a central portion,the conical valve seat 30 b extending downwardly from the smallerdiameter of aperture 30 a′ and having a diameter gradually increasedtoward the lower edge of the aperture 30 a, and the annular groove 30 cprovided on the upper side of the valve seat unit 30 so as to surroundthe aperture 30 a. The annular groove 30 c provides the cylindrical part30 d on a central portion of the upper side of the valve seat unit 30.The outer wall of the annular groove 30 c forming the cylindrical part30 b forms the upper disk-like part 30 e. The valve seat unit has alower side than the upper disk-like portion 30 e formed as a lowerdisk-like portion 30 f having a greater diameter than the upperdisk-like portion 30 e. The valve seat unit 30 is melt-bonded andintegrally fitted to the disk-shaped portion 21, housing the lowerdisk-like portion 30 f in the larger diameter stepped hole 22 a at thelowest position so that the upper disk-like portion 30 e has the upperend pressed against the conical hole 22 b, and the lower disk-likeportion 30 f has the upper end gotten in close contact with the upperend of the larger diameter of stepped hole 22 a.

[0212] The float 40, which is incorporated into the cylindrical body 20thus constructed, made of, e.g., polyacetal. The float is housed in thecylindrical portion 23 so as to be guided by the guide ribs to bevertically movable in smooth fashion, following a change in the fuelliquid level. The float has the upper side provided with the valve body40 a, which gets in contact with the valve seat 30 b to close theaperture 30 a of the valve seat unit 30 in upward movement toward thevalve seat 30 b, following a change in the fuel liquid level. The floathas a substantially central portion on the lower side formed with therecess 40 b upwardly extending. The float has the annular recess 40 b′provided in the recess 40 b so as to extend further upwardly. The floatalso has the circular base 40 c formed in the recess 40 b. The float hasthe hole 40 d communicating between the recess 40 b and the upper endsurface of the float 40. The lid 24, which keeps the float 40 formingthe fuel cutoff valve 3 in an incorporated state in the cylindricalportion 23, includes the cylindrical peripheral wall 24 b, which extendsupwardly from the peripheral edge of the bottom wall 24 a in a circularplate shape. The lid receives the cylindrical portion 23 in thecylindrical peripheral wall 24 b so as to get the leading edge of thecylindrical portion 23 in touch with the bottom wall 24 a. The lid isfitted to the cylindrical portion 23 by engaging the engagementprojection 23 b provided on the cylindrical portion 23 with an edge ofthe engagement slot 24 c formed in the cylindrical peripheral wall 24 b.By the helical compression spring 41, which is disposed on the circularbase 24 d provided on the substantially central portion on the innerside of the lid 24 and on the circular base 40 c on the float 40, thefloat 40 can easily float up and move in the cylindrical portion 23,following a change in the fuel liquid level.

[0213] The lid 24, which incorporates the float 40 into the cylindricalportion 23, has the bottom wall 24 a formed with the plural apertures 24e vertically passing therethrough, allowing fuel or gas to easily flowin and out of the cylindrical portion 23.

[0214] When the float 40 does not receive the buoyancy from the fuelliquid, the helical compression spring 41 balances with the weight ofthe float 40 and elastically supports the float 40 so as to maintain thevalve body 40 a in a position away from the valve seat 30 b. When thefloat 40 receives the buoyancy from the fuel liquid, the helicalcompression spring allows the float 40 to float up easily and moveupwardly by the buoyancy. In the latter case, the helical compressionspring causes the float 40 to press its valve body 40 a into contactwith the valve seat 30 b against the buoyancy, e.g., if the vehicle withthe fuel tank turns over.

[0215] In the connector A, which includes the tubular unit 1 and theflange unit 2 comprising the outer shell 50 and the gas barrier member10 thus constructed and also includes the fuel cutoff valve 3, the valveseat unit 30 is integrally melt-bonded and fitted to the disk-shapedportion 21 forming the fuel cutoff valve 3. The cylindrical portion 23has the float 40 housed therein and the lid 24 fitted to the open bottomthereof with the helical compression spring 41 interposed between thehoused float 40 and the lid.

[0216] In the shown embodiment, the connector A thus constructed has theside of the cylindrical portion 23 inserted into the fuel tank B throughthe opening Ba formed in the upper side of the fuel tank B. The annularprojected portion 12 a of the gas barrier member 10 and the annularprojected portion 51 in the connector A are melt-bonded to the fuel tankB.

[0217] By fitting the connector A to the inner area Bc of the openingformed in the fuel tank B as explained, the gas barrier member 10 caneffectively decrease the leakage of evaporative emissions deriving fromthe fuel from the fuel tank B.

[0218] The connector A can be easily and reliably fitted to the fueltank B since fitting the connector A to the fuel tank B is carried outby melt-bonding the connector A to the fuel tank B.

[0219] In this embodiment, the annular projected portion 51, which isprovided on the outer shell 50 made of polyethylene or high-densitypolyethylene and projects toward the outer surface of the fuel tank B soas to cover the leading edge of the flanged portion 12 of the gasbarrier member 10, is melt-bonded to the fuel tank. While the gasbarrier member 10 can effectively decrease the leakage of evaporativeemissions from the fuel tank B, the connector A can be fitted to, withhigh melt-bonding strength ensured, to the fuel tank B, which has theouter surface layer Be made of polyethylene or high-densitypolyethylene.

[0220] In this embodiment, the outer shell 50 made of polyethylene orhigh-density polyethylene is formed on the gas barrier member 10 in sucha state that a projection 52, which is provided on one of the annularprojected portion 51 of the outer shell 50 made of polyethylene orhigh-density polyethylene and the leading end of the flanged portion 12of the gas barrier member 10, bites into the other one of the annularprojected portion 51 and the leading portion of the flanged portion 12.

[0221] In this embodiment, specifically, the annular projected portion12 a, which is formed on the leading edge of the flanged portion 12 ofthe gas barrier member 10, has an outer side formed with an annulargroove 12 c, and the annular projected portion 51 of the outer shell 50has an inner side formed with an annular projection 52′ bitten into theannular groove 12 c. In other words, in this embodiment, a moldingprocess, wherein the annular groove 12 c is formed in the outer side ofthe annular projected portion 12 a of the gas barrier member 10, iscarried out to obtain a partly molded product with the gas barriermember 10 thus molded, and then, the partly molded product is used as aninsert to mold the outer shell 50, forming the annular projection 52′ onthe inner side of the annular projected portion 51 of the outer shell 50so as to be bitten in the annular groove 12 c.

[0222] Thus, the integration between the annular projected portion 12 aformed on the leading edge of the flanged portion 12 in the gas barriermember 10 and the annular projected portion 51 of the outer shell 50 canbe ensured with high level in this embodiment. In particular, when bothof the annular projected portions 12 a and 51 are heated and melted by aheating plate for melt-bonding, both of the annular projected portions12 a and 51 can be melt-bonded to the fuel tank B, being adequatelymelted in a planned range.

[0223] The projection 52 may be formed on the outer side of the annularprojected portion 12 a of the gas barrier member 10. In this case, theouter shell 50 is formed so as to have the projection 52 bitten therein.

[0224] The projection 52 may comprise a plurality of projections, whichare provided in discontinuous fashion so as to be located along theinner area Bc of the opening formed in the fuel tank B.

[0225] In this embodiment, the annular projected portion 12 a formed onthe leading edge of the flanged portion 12 in the gas barrier member 10,and the annular projected portion 51 of the outer shell 50 made ofpolyethylene or high-density polyethylene project downwardly bysubstantially the same length. In other words, both of the annularprojected portion 12 a and 51 have projected surfaces 12 d and 53 facingthe outer surface of the fuel tank B positioned substantially flush witheach other.

[0226] The annular projected portion 12 a of the gas barrier member 10and the annular projected portion 51 of the outer shell 50 made ofpolyethylene or high-density polyethylene have a space 60 formedtherebetween so as to open toward the outer surface of the fuel tank B.

[0227] Specifically, in this embodiment, the annular projected portion12 a of the gas barrier member 10 is formed so that an outer surface ofthe annular projected portion 12 a between the annular groove 12 cformed in the outer side of the annular projected portion 12 a and theprojected surface 12 d of the annular projected portion 12 a forms aslant surface toward the peripheral edge Bb of the opening of the fueltank B so as to have a size gradually enlarged toward the projectedsurface 12 d. The annular projected portion 51 of the outer shell 50 hasan inner surface facing the slant surface extending substantiallyperpendicular to the outer surface of the fuel tank B, thus providingthe space 60 in an annular shape between the slant surface and the innersurface.

[0228] In this embodiment, when the annular projected portion 51 of theouter shell 50 is heated and melted, the melted material of polyethyleneor high-density polyethylene forming the annular projected portion 50can come into the space 60. As a result, the melt-bonding strength withrespect to the fuel tank B having the outer surface layer Be made of, inparticular, high-density polyethylene can be further improved since theannular projected portion 50 can be melt-bonded to the fuel tank B,spreading the melted material of polyethylene or high-densitypolyethylene in a wide range.

[0229] Unlike in the example shown in FIGS. 10-16, the annular projectedportion 12 a provided on the flanged portion 12 in the gas barriermember 10 may project so as to have a smaller projecting length than theannular projected portion 51 of the outer shell 50 made of polyethyleneor high-density polyethylene (FIG. 17).

[0230] In other words, the projected surface 12 d of the annularprojected portion 12 a in the gas barrier member 10 is lower (i.e.,lower in a direction away from the outer surface of the fuel tank B)than the projected surface 53 of the annular projected portion 51 in theouter shell 50, which faces the outer surface of the fuel tank B asshown in FIG. 17.

[0231] In this case, when the annular projected portion 51 in the outershell 50 is heated and melted, the melted material forming the annularprojected portion 51 and made of polyethylene or high-densitypolyethylene can come into between the projected surface 12 d of theannular projected portion 12 a in the gas barrier member 10 and theouter surface of the fuel tank B. The melt-bonding strength with respectto the fuel tank B having the outer surface layer Be made of, inparticular, high-density polyethylene can be further improved since theannular projected portion 51 can be melt-bonded to the fuel tank B,spreading the melted material of polyethylene or high-densitypolyethylene in a wide range in this case as well.

[0232] Unlike in the example shown in FIGS. 10-16, the melt-bonding maybe carried out so as to leave some part of the space 60 unfilled evenafter the annular projected portion 51 in the outer shell 50 has beenmelt-bonded to the fuel tank B (FIG. 19 and FIG. 20).

[0233] In the example shown in FIG. 20, both of the annular projectedportion 51 in the outer shell 50 and the annular projected portion 12 ain the gas barrier member 10 are melt-bonded to the outer surface layerBe of the fuel tank B made of high-density polyethylene, and the space60 is formed so as to have an enough size to prevent the space 60 frombeing fully filled by the melt-bonding.

[0234] In this case, even if the gas barrier member 10 is swollen byfuel or evaporative emissions from the fuel, the unfilled part of thespace 60 can absorb the swell to make it difficult that the melt-bondedportion between the annular projected portion 51 in the outer shell 50and the fuel tank B has a force reducing the melt-bonding strengthapplied thereto.

[0235] Unlike in the example shown in FIGS. 10-16, the upper side of thegas barrier member 10, which is covered by the outer shell 50 made ofpolyethylene or high-density polyethylene, may be stepped to have astepped surface 70 facing the leading edge of the flanged portion 12 inthe gas barrier member 10 (FIG. 21 and FIG. 22).

[0236] In the example shown in FIG. 22, both of the annular projectedportion 51 in the outer shell 50 and the annular projected portion 12 inthe gas barrier member 10 are melt-bonded to the outer surface layer Beof the fuel tank B made of high-density polyethylene, and the upper sideof the gas barrier member 10 thus melt-bonded is stepped so as to havethe stepped surface 70 facing the leading edge of the flanged portion 12in the gas barrier member 10. The outer shell 50 has an opposed innersurface 71 formed accordingly so as to be in contact with the steppedsurface 70.

[0237] Even if the gas barrier member 10 is swollen by the fuel orevaporation emissions from the fuel in the fuel tank connector thusconstructed, the opposed inner surface 71 of the outer shell 50 made ofpolyethylene or high-density polyethylene in contact with the steppedsurface 70 can receive the force caused by the swell to disperse theforce, making it difficult that the melt-bonded portion between theannular projected portion 51 in the outer shell 50 and the fuel tank Bhas a force reducing the melt-bonding strength applied thereto.

[0238] The connector A, which has been fitted to the fuel tank B asexplained, may be used for connection with a suitable pipe C.

[0239] In order to that the connector A can easily and reliably maintainthe connection with the pipe C, the tubular unit 1 of the connector hasthe outer peripheral surface of the horizontal tubular portion 1 bformed with the plural ridges, which comprise the conical guides 1 chaving a diameter gradually reduced toward the leading edge and thevertical stepped surfaces 1 d extending from respective edges of theconical guides remote from the leading edge to the outer peripheralsurface of the horizontal tubular portion 1 b, in the shown embodiment.

[0240] Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

What is claimed is:
 1. A fuel tank connector adapted to be fitted to anopening of a fuel tank to connect the fuel tank and a pipe incommunicating fashion, comprising: a gas barrier member made of asynthetic resin having a gas barrier property, the gas barrier memberincluding a tubular portion and a flanged portion provided on aperipheral side of the tubular portion, which extends beyond an openingof the fuel tank; wherein the gas barrier member is made of polybutyleneterephthalate, polyphenylene sulfide, a liquid crystal polymer,aliphatic polyketone, aromatic polyamide, a blended polymer of anethylene-vinyl alcohol copolymer and high-density polyethylene, ablended polymer of polyamide and polyethylene, a blended polymer ofpolyamide and high-density polyethylene, or polyethylene terephthalate;the gas barrier member has at least a portion of a surface covered withan outer shell made of an olefin resin having an adhesive property,polyethylene or high-density polyethylene; the outer shell includes anannular projected portion, which covers a leading end of the flangedportion and projects toward an outer surface of the fuel tank, andwherein the gas barrier member has the leading end of the flangedportion provided with an annular projected portion, which projectstoward the outer surface of the fuel tank and has a projecting lengthsubstantially equal to that of the annular projected portion of theouter shell, and the annular projected portion of the gas barrier memberand the annular projected portion of the outer shell has a cavity formedtherebetween to be opened on a side of the outer surface of the tank,the outer shell being made of polyethylene or high-density polyethylene.2. The fuel tank connector according to claim 1, which is used forconnection with a fuel feeding pipe.
 3. The fuel tank connectoraccording to claim 1, which is used for connection with a vent pipe. 4.The fuel tank connector according to claim 1, further comprising a fuelcutoff valve.